Geological Survey (U.S.)Contour interval 10 feet.;"Topography from aerial photographs by Kelsh plotter and by planetable surveys 1956-1957. Aerial photographs taken 1956."; (W 89⁰00ʹ00ʺ--W 88⁰45ʹ00ʺ/N 40⁰15ʹ00ʺ--N 40⁰00ʹ00ʺ);Relief shown by contours and spot heights.;1 map, colored;45 x 35 cm.;1:62,500JPEG2000https://digital.library.illinois.edu/items/99bd1d10-82d4-0134-1f08-0050569601ca-4engGeological Survey (U.S.)Geological Survey Division (Urbana, Ill.)PublicMaroa quadrangle, Illinois : 15 minute series (topographic).MapsIllinois1958University of Illinois Urbana-Champaign